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USGS Spectral Library Version 7 Sample Description

Kokaly, R.F., Clark, R.N., Swayze, G.A., Livo, K.E., Hoefen, T.M., Pearson, N.C., Wise, R.A., Benzel, W.M., Lowers, H.A., Driscoll, R.L., and Klein, A.J., 2017, USGS Spectral Library Version 7: U.S. Geological Survey Data Series 1035, 61 p., https://doi.org/10.3133/ds1035
For more information on the library, see: local link web link

TITLE: Actinolite NMNH80714 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: NMNH80714

MINERAL_TYPE: Inosilicate

MINERAL: Actinolite (Amphibole group)

FORMULA: Ca2(Mg,Fe+2)5Si8O22(OH)2

FORMULA_HTML: Ca2(Mg,Fe+2)5Si8O22(OH)2

COLLECTION_LOCALITY: Cumberland, Rhode Island

ORIGINAL_DONOR: National Museum of Natural History

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

Forms series with Tremolite and Ferro-actinolite.

Sample was sieved to less than 250 µm.
It probably contains enough iron to be considered a ferro-actinolite.

IMAGE_OF_SAMPLE:
NO PHOTO

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

40 kV - 30 mA, 6.5-9.5 keV
File: act80714.mdi (smear mount on quartz plate)
References: JC-PDS #41-1366, 44-1402, 45-1371
Found: Monoclinic amphibole, probably actinolite

Comment: Sharp amphibole peaks with clearly resolved alpha1-alpha2 components but slight peak broadening (compared with WAR-404) suggest excellent crystallinity and little compositional heterogeneity. The pattern similar to referenced JCPDS patterns. Subsequent search-match based on eight strongest lines returned 16 amphiboles among the 20 most-likely hits; profile based match returned one amphibole among five hits. In each case, the most likely hit was actinolite, #41-1366.

END_XRD_ANALYSIS.

COMPOSITIONAL_ANALYSIS_TYPE: EPMA # XRF, EPMA, ICP(Trace), WChem


COMPOSITION
KEYWORD		 Oxide
ASCII		 Amount Weight
Percent, %		 Oxide
html
COMPOSITION: SiO2 54.28 wt% SiO2
COMPOSITION: TiO2 0.02 wt% TiO2
COMPOSITION: Al2O3 2.81 wt% Al2O3
COMPOSITION: Cr2O3 0.00 wt% Cr2O3
COMPOSITION: FeO 8.60 wt% FeO
COMPOSITION: MnO 0.59 wt% MnO
COMPOSITION: MgO 18.53 wt% MgO
COMPOSITION: CaO 13.04 wt% CaO
COMPOSITION: Na2O 0.74 wt% Na2O
COMPOSITION: Total 98.61 wt%
COMPOSITION: O=Cl,F,S wt% #correction for Cl, F, S
COMPOSITION: New Total wt%

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

EM analysis by Gregg A. Swayze at USGS Branch of Geophysics, Denver, Colorado.

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

Mineral mode:

90 vol% Actinolite pop1 avg. grain size = 255µm
25% coated with smaller actinolite grains
2 vol% Actinolite pop2 avg. grain size = 30µm
8 vol% Biotite? pop3 avg. grain size = 230µm
coated with small actinolite grains

avg. grain size of populations = 250µm

Pure sample of prismatic green-blue fibers. Slight pleochroism, biaxial (-), two good cleavages, high birefringence, inclined extinction with angle = 12 degrees. All this is consistent with actinolite. G. Swayze

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1b2_3_4_ # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns